A shear mechanism having a pair of blades which cooperate to shear a continuous stream of molten glass into gobs is known. For example, see U.S. Pat. No. 2,680,937. Prior art devices, such as the mechanism disclosed in the patent, comprise cams, rods, levers, etc. which control the speed and angular displacement of the shear mechanism arms. These devices provide poor performance due to vibrations, space limitations, etc. Such devices have limited flexibility since it is necessary to stop the machine and change the cams to change the profile or angular position-time curve of the arms. Due to the construction of the prior art shear mechanism, it was not possible to synchronize the feeder and shear mechanisms in different phase relationships without seriously interrupting machine operation.
A shear mechanism which solves the above problems is disclosed in co-pending U.S. patent application Ser. No. 388,051, filed on even date, assigned to the assignee herein. The shear mechanism includes a housing adapted to be attached to the feeder bowl. First and second shafts are provided in the housing. A discrete arm is connected to each shaft. At least one discrete blade is connected to each arm. The blades are brought into overlapping relation to cut the glass stream. A reversible electric motor is supported by the housing. The motor has its output shaft mechanically connected to the first and second shafts for oscillating the arms in unison in opposite directions between open and closed positions.